Microcontrollers and Microprocessors


Wi-Fi modules today are best known in applications in which they are interfaced to Laptops and Mobile Phone processors using the Cardbus, PCI-e or SDIO host interfaces. All these Wi-Fi cards use a device driver and WLAN configuration manager in the host system, usually occupying 100 kB or more of memory. The host itself is a high-end processor that runs a full-functional operating system and performs other general-purpose tasks which are much more memory and compute intensive than the Wi-Fi radio driver. On the other hand, Embedded systems are characterized by their use of one of a variety of micro-controllers ranging from 8-bit versions, with a few kilobytes of instruction memory, low-speed serial interfaces and a few GPIO on the lower-end, to 32-bit ARM9 platforms with audio/video, SDIO, USB and other peripheral interfaces on the higher-end. The wireless connectivity requirements of such systems are therefore varied in terms of the available host interface, limited host memory and required throughputs. Many such systems run a simple RTOS or no OS at all. Even where they include an OS, some may not possess a networking stack. So the choice of how Wi-Fi is to be integrated into an embedded system depends on all of these parameters. And there is a Redpine module for many of these scenarios.

Microcontrollers and Microprocessors
Product Family
n-Link
Connect-io-n
Wireless Protocol
802.11n
802.11n
802.11n
802.11n
Host Interface
SDIO
SPI
SPI
UART
Target microcontroller families
32-bit full performance
Medium performance
8-bit, 16-bit medium or low speed.
8-bit, 16-bit low speed
Host-interface Bandwidth
100Mbps (25MHz clock)
25Mbps (25MHz clock)
25Mbps (25MHz host clock)
115Kbaud – 1Mbaud
Wireless Single-antenna 11n throughputs at host interface
35Mbps
>20Mbps
10-15Mbps
115Kbaud – 1Mbaud
Wi-Fi Driver size (on Host)
>100KB
>100KB
<10KB
<2KB
WPA2 Security
Yes
Yes
Yes
Yes
QoS: WMM-PS 
Yes 
Yes
No
No
Variants with Embedded TCP/IP in wireless module?
No
No
Yes 
Yes
Integration Effort
Moderate
Moderate
Low
Low